High magnification microscopes are often damaged when a specimen collides into the objective lens while the operator is focusing. Many high magnification lenses are designed to accommodate this by using lenses which non-destructively collapse under light pressure. Typically, the microscope operator will notice the collision and stop the focusing attempt.
A problem arises when a microscope is used in a remote location where the operator is some distance away, as is typically done in nuclear research. The operator has no feel and no direct visual contact with the microscope. Consequently, the operator does not know to stop the focus drive before severe damage occurs.
Over-travel control switches mounted on the stage are not useful if specimen sizes change. A limit switch position for small specimens will not suffice for large specimens. Infrared positioning is also not useful because the high radiation typically encountered in nuclear research will quickly damage the infrared system.
In light of these considerations, a need arises for a remote-control microscope which is protected from collision damage regardless of specimen size or shape.